This application claims the priority of German patent document 100 37 396.8, filed Aug. 1, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an element for carrying out and documenting a program or test sequence in, for example, a motor vehicle.
Technical systems such as are used in vehicles are characterized by a range of characteristics, and are complex, being composed of components that interact via communications links, such as bus systems. Furthermore, such systems are heterogeneous, at least with regard to their interaction. Control systems are provided, in the same way as in reactive systems. Combinations of both types of systems likewise exist. Furthermore, these systems are hybrid. Electrical, mechanical, hydraulic, optical and/or pneumatic components thus occur.
Both open-loop and closed-loop control of such systems is provided by specific control components, which are a part of the systems. In vehicles, these components are referred to as controllers, which are normally electronic components, whose function is coded in a program that is carried out in a computation unit.
These complex technical systems must be tested, for quality assurance purposes, particularly the controllers which, in the end, provide the monitoring for the technical processes. The program or test systems used in this case are intended to provide the capability to influence all those variables which are relevant for the test at the interface with the control component or control components, and also to make these variables visible when required (test, program sequence, simulation and recording)
For controller testing, the controller is simulated in a simulated technical environment (software-in-the-loop SIL) in the early development phases. As soon as the control components are actually available, the test of the complete component is continued on a hardware-in-the-loop (HIL) test system. Those components which belong to the complete control system are also tested linked together using such HIL test systems. In the final step, the controllers are integrated and tested once again jointly with the other components that make up the overall system.
One object of the present invention is to simplify and improve the testing of such controllers.
According to the invention, this object is achieved by the use of simulation elements which allow specific functions to be carried out. The element has at least one control input to which an external control signal can be supplied, and a variable can be varied in the element as a function of the external control signal. The process of carrying out the function can be varied by the element in such a manner that when the variable has the value “0” and the external control signal is at a first signal level, the variable assumes a specific value not equal to “0”; and when the variable is at that specific value and an external control signal which is at the first signal level is once again applied, the variable remains at that specific value.
It has been found that a simulation and test can be carried out easily using elements such as these. These elements can easily be provided with appropriate parameters, so that said parameters can then be matched to the respective specific cases.
The linking of such elements allows even complex systems to be simulated, documented, run and/or tested. Different elements with different functions are advantageously provided for this purpose. It can be found that the number of these elements can be limited while nevertheless allowing even complex simulations to be carried out with comparatively little effort.
In one embodiment of the invention, the variable is reset to the value “0” when the element has finished carrying out the function. When the variable is reset, the element outputs an external control signal, which is at the first signal level, via at least one control output of the element. This advantageously allows elements to be linked in series. The individual elements can then initiate further action by outputting appropriate external control signals once they have completed their own function.
In another embodiment of the invention, the variable assumes the value “0” when the at least one control input of the element is supplied with an external control signal which is at a second signal level, with an external control signal which is at the second signal level then being output via the at least one control output of the element. This allows deactivation to passed on from the element. Thus, overall, the element can remain in an activated state and can carry out the function until deactivated by an appropriate external control signal. On the other hand, the element can deactivate itself when it has completed its function.
There is advantageously no restriction to carrying out just one element at one time. Parallel-running processes can thus also advantageously be simulated.
In still another embodiment of the invention, the element has one control input and a number of control outputs, with the external control signal being output from the element via all the control outputs. Such an element advantageously makes it possible to initialize the process of carrying out the simulation of parallel-running processes.
In a further embodiment of the invention, the element has a number of control inputs, with an external control signal which is at the first signal level being output via the at least one control output when a control signal which corresponds to the first signal level is applied to all the control inputs. This element allows the activation of a downstream element which is stimulated via the control output of this element to be controlled such that this activation takes place only when an activation signal is applied to all the control inputs. This thus represents a logic AND operation.
The element in another embodiment of the invention has a number of control inputs, with an external control signal which is at the first signal level being output via the at least one control output when a control signal which corresponds to the first signal level is applied to at least one control input. In contrast to the previous embodiment, it has a logic OR operation.
In still another embodiment of the invention, the element has one control input and a number of control outputs as well as at least one data input. An external control signal, which is applied to the control input and is at the first signal level, is output via that control output which is determined by the function of the element as a function of the signal which is applied to the at least one data input. This advantageously makes it possible for the further program sequence, in particular a test sequence, to branch depending on whether specific states and data values are reached.
In yet another embodiment of the invention, the element has one or more data inputs and one or more data outputs, in which case the function comprises the formation of one or more data output signals from the data input signals which are applied to the data input or inputs, which data output signal or signals is or are output via the data output or outputs. In this case, the data input signals can in the simplest case be passed on unchanged via the data outputs. These data input signals can likewise also be modified. This may be done, for example, by arithmetic operations such as addition, subtraction, multiplication and division. It is likewise also possible to form the absolute value, to carry out integration or differentiation, or to provide transcendental functions. The function may likewise also comprise the assessment of the data input signals by means of Boolean algebra, using NOT, AND, OR and XOR operations.
It is also possible for the function to represent a comparison, which may include the values of a number of data input signals. One or more data input signals may likewise be investigated to determine whether they are within a specific value range. It is also possible to investigate the change in the data input signal by, for example, using the comparison process to investigate whether the respective data input signal is above or below a threshold. Such a comparison element advantageously does not output any external control signal. The element carries out the comparison function once it has received an external control signal at the first signal level via a control input. The comparison process is then ended when an appropriate external control signal for deactivation is applied via the control input.
The function may also comprise the storage of specific values. This may be, for example, the final value of the data input signal, the minimum value which the data input signal has assumed, the maximum value which the data input signal has assumed, or the mean value of the data input signal.
According to a further feature of the invention, the function of the element is a time measurement. The element may have, for example, at least one data input such that, once the element has been activated by an external control signal, the time period is determined which passes before a specific further data input signal occurs after a specific first data input signal.
According to another embodiment of the invention, time measurement may be carried out by measuring a specific time period starting from a time defined by the application of an external control signal at the first signal level or by a specific signal at a data input or by a signal combination at a number of data inputs of the element, with an external control signal at the first signal level being output at the end of the time period via a control output of the element, and/or a corresponding data signal being output at one or more data outputs. A refinement such as this represents a time-related count down, in particular a time-out element.
According to another feature of the invention, the element can be supplied with an external control signal via a control input, with a time signal profile being output as the data output signal via a data output when the external control signal is at the first signal level. In this case, various functions can be provided by an appropriate logic operation on basic functions.
It has advantageously been found that the described elements make it possible to provide test systems which allow an automated sequence or test. In particular, it is thus no longer necessary to check the large number and complexity of control functions by manual testing, which is problematic in any case from the viewpoints of effectiveness and efficiency.
The elements according to the invention allow both the simulation and the recording and evaluation of variables which are relevant for the test or the software. This is done by simulation of the component under test or of the system under test, with subsequent evaluation of the corresponding reactions.
It has furthermore been found that simulation and evaluation are possible in real time. In addition, it has been found that a program system or test system which comprises the described elements is also able to carry out a number of functions at the same time. Furthermore, both digital variables and analogue variables can be processed by appropriate configuration of the elements.
Two methods are known, in conjunction with computer-aided simulation, from the prior art. One relates to compilation, which requires that the program be translated to a machine-legible form before the running time. The machine-legible form can then in turn be run only on the machine for which this machine-legible form was compiled. Furthermore, interpretation is known, in which the program is analysed and carried out during the running time. This has disadvantages with regard to the running times which can be achieved.
The combination of the elements proposed here means that the elements can be matched to the specific conditions by pre-setting appropriate parameters. Firstly, this allows good flexibility to be achieved. Nevertheless, the simulation running times are sufficiently fast, and the simulations can also be carried out in a flexible manner on different computers.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.